ofDocsexamples sound audioInputExample src ofApp.cpp
#include "ofApp.h"

//--------------------------------------------------------------
void ofApp::setup(){	 
	
	ofSetVerticalSync(true);
	ofSetCircleResolution(80);
	ofBackground(54, 54, 54);	
	
	soundStream.printDeviceList();
	
	int bufferSize = 256;

	left.assign(bufferSize, 0.0);
	right.assign(bufferSize, 0.0);
	volHistory.assign(400, 0.0);
	
	bufferCounter	= 0;
	drawCounter		= 0;
	smoothedVol     = 0.0;
	scaledVol		= 0.0;


	ofSoundStreamSettings settings;

	// if you want to set the device id to be different than the default
	// auto devices = soundStream.getDeviceList();
	// settings.device = devices[4];

	// you can also get devices for an specific api
	// auto devices = soundStream.getDevicesByApi(ofSoundDevice::Api::PULSE);
	// settings.device = devices[0];

	// or get the default device for an specific api:
	// settings.api = ofSoundDevice::Api::PULSE;

	// or by name
	auto devices = soundStream.getMatchingDevices("default");
	if(!devices.empty()){
		settings.setInDevice(devices[0]);
	}

	settings.setInListener(this);
	settings.sampleRate = 44100;
	settings.numOutputChannels = 0;
	settings.numInputChannels = 2;
	settings.bufferSize = bufferSize;
	soundStream.setup(settings);

}

//--------------------------------------------------------------
void ofApp::update(){
	//lets scale the vol up to a 0-1 range 
	scaledVol = ofMap(smoothedVol, 0.0, 0.17, 0.0, 1.0, true);

	//lets record the volume into an array
	volHistory.push_back( scaledVol );
	
	//if we are bigger the the size we want to record - lets drop the oldest value
	if( volHistory.size() >= 400 ){
		volHistory.erase(volHistory.begin(), volHistory.begin()+1);
	}
}

//--------------------------------------------------------------
void ofApp::draw(){
	
	ofSetColor(225);
	ofDrawBitmapString("AUDIO INPUT EXAMPLE", 32, 32);
	ofDrawBitmapString("press 's' to unpause the audio\n'e' to pause the audio", 31, 92);
	
	ofNoFill();
	
	// draw the left channel:
	ofPushStyle();
		ofPushMatrix();
		ofTranslate(32, 170, 0);
			
		ofSetColor(225);
		ofDrawBitmapString("Left Channel", 4, 18);
		
		ofSetLineWidth(1);	
		ofDrawRectangle(0, 0, 512, 200);

		ofSetColor(245, 58, 135);
		ofSetLineWidth(3);
					
			ofBeginShape();
			for (unsigned int i = 0; i < left.size(); i++){
				ofVertex(i*2, 100 -left[i]*180.0f);
			}
			ofEndShape(false);
			
		ofPopMatrix();
	ofPopStyle();

	// draw the right channel:
	ofPushStyle();
		ofPushMatrix();
		ofTranslate(32, 370, 0);
			
		ofSetColor(225);
		ofDrawBitmapString("Right Channel", 4, 18);
		
		ofSetLineWidth(1);	
		ofDrawRectangle(0, 0, 512, 200);

		ofSetColor(245, 58, 135);
		ofSetLineWidth(3);
					
			ofBeginShape();
			for (unsigned int i = 0; i < right.size(); i++){
				ofVertex(i*2, 100 -right[i]*180.0f);
			}
			ofEndShape(false);
			
		ofPopMatrix();
	ofPopStyle();
	
	// draw the average volume:
	ofPushStyle();
		ofPushMatrix();
		ofTranslate(565, 170, 0);
			
		ofSetColor(225);
		ofDrawBitmapString("Scaled average vol (0-100): " + ofToString(scaledVol * 100.0, 0), 4, 18);
		ofDrawRectangle(0, 0, 400, 400);
		
		ofSetColor(245, 58, 135);
		ofFill();		
		ofDrawCircle(200, 200, scaledVol * 190.0f);
		
		//lets draw the volume history as a graph
		ofBeginShape();
		for (unsigned int i = 0; i < volHistory.size(); i++){
			if( i == 0 ) ofVertex(i, 400);

			ofVertex(i, 400 - volHistory[i] * 70);
			
			if( i == volHistory.size() -1 ) ofVertex(i, 400);
		}
		ofEndShape(false);		
			
		ofPopMatrix();
	ofPopStyle();
	
	drawCounter++;
	
	ofSetColor(225);
	string reportString = "buffers received: "+ofToString(bufferCounter)+"\ndraw routines called: "+ofToString(drawCounter)+"\nticks: " + ofToString(soundStream.getTickCount());
	ofDrawBitmapString(reportString, 32, 589);
		
}

//--------------------------------------------------------------
void ofApp::audioIn(ofSoundBuffer & input){
	
	float curVol = 0.0;
	
	// samples are "interleaved"
	int numCounted = 0;	

	//lets go through each sample and calculate the root mean square which is a rough way to calculate volume	
	for (size_t i = 0; i < input.getNumFrames(); i++){
		left[i]		= input[i*2]*0.5;
		right[i]	= input[i*2+1]*0.5;

		curVol += left[i] * left[i];
		curVol += right[i] * right[i];
		numCounted+=2;
	}
	
	//this is how we get the mean of rms :) 
	curVol /= (float)numCounted;
	
	// this is how we get the root of rms :) 
	curVol = sqrt( curVol );
	
	smoothedVol *= 0.93;
	smoothedVol += 0.07 * curVol;
	
	bufferCounter++;
	
}

//--------------------------------------------------------------
void ofApp::keyPressed  (int key){ 
	if( key == 's' ){
		soundStream.start();
	}
	
	if( key == 'e' ){
		soundStream.stop();
	}
}

//--------------------------------------------------------------
void ofApp::keyReleased(int key){ 
	
}

//--------------------------------------------------------------
void ofApp::mouseMoved(int x, int y ){
	
}

//--------------------------------------------------------------
void ofApp::mouseDragged(int x, int y, int button){
	
}

//--------------------------------------------------------------
void ofApp::mousePressed(int x, int y, int button){
	
}

//--------------------------------------------------------------
void ofApp::mouseReleased(int x, int y, int button){

}

//--------------------------------------------------------------
void ofApp::mouseEntered(int x, int y){

}

//--------------------------------------------------------------
void ofApp::mouseExited(int x, int y){

}

//--------------------------------------------------------------
void ofApp::windowResized(int w, int h){

}

//--------------------------------------------------------------
void ofApp::gotMessage(ofMessage msg){

}

//--------------------------------------------------------------
void ofApp::dragEvent(ofDragInfo dragInfo){ 

}